Metal-free, photoinduced remote C(sp 3 )-H borylation.

Here, we describe a protocol for the metal-free, photo-induced borylation of unactivated C(sp 3 )-H bonds distal to an O -oxalate hydroxamic ester functionality. The methodology requires only substrate and bis(catecholato)diboron under light irradiation to effect the desired transformation. A range of linear and cyclic tertiary and secondary borylation products are obtained in good yields and high site-selectivity enabling the late-stage C(sp 3 )-H borylation of natural product derivatives and drug-like compounds.